Add type-check for `renderer` parameter in `texture_init` to prevent crashes

[coderabbitai]

Summary

In src_c/render.c, the texture_init function parses the renderer argument using the generic O format specifier in PyArg_ParseTupleAndKeywords, but then immediately casts and dereferences it as a pgRendererObject * without any type validation. Passing a non-Renderer Python object will cause invalid memory access / a crash.

Suggested Fix

Use the O! format specifier with &pgRenderer_Type to enforce the type at parse time:

-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "OO|ippp", keywords,
-                                     &renderer, &sizeobj, &depth, &staticc,
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!O|ippp", keywords,
+                                     &pgRenderer_Type, &renderer, &sizeobj,
+                                     &depth, &staticc,
                                      &streaming, &target)) {
         return -1;
     }

References

• Identified in PR Remove scale_quality parameter of _render.Texture #3741 (comment: Remove scale_quality parameter of _render.Texture #3741 (comment)) — deferred as out of scope for that PR.
• Requested by @oddbookworm.